package LanQiao;

import java.util.Arrays;
import java.util.Scanner;

public class Demo4 {
    public static void main(String[] args) {
        String[] arr = new String[4];

        Scanner scanner = new Scanner(System.in);

        for (int i = 0; i < 4; i++) {
            arr[i] = scanner.nextLine();
        }

        Arrays.sort(arr);

        StringBuilder builder = new StringBuilder();

        for (String str : arr) {
            builder.append(str);
        }

        System.out.println(builder.toString());
    }
}
